1. What is the difference between tissue fluid and lymph? Tissue fluid is the fluid that has leaked out of the capillaries into the spaces around the cells of the tissues. Lymph is tissue fluid that has entered the lymphatic system i.e. the difference is largely one of location.

2. By what route does lymph make its way back to join the blood of the circulatory system? Lymph makes it way back to join the blood in the circulatory system via the lymphatic capillaries, lymphatic vessels, at least one lymph node and the thoracic duct. The lymph then joins the blood in veins that carry it back to the heart.

3. As the lymphatic system has no heart to push the lymph along what makes it flow? As the lymphatic system has no heart to push the lymph along it is pushed along mainly by the contraction of skeletal muscles that lie alongside the lymphatics.

4. What happens to the lymph as it passes through a lymph node? As the lymph passes through a lymph node, bacteria and debris are filtered from it and lymphocytes are added to it.

5. Where is the spleen located in the body? The spleen is found in the abdomen alongside and slightly caudal to the stomach.

6. Where is the thymus located in the body? The thymus gland is located in the thorax beneath the sternum and just cranial to the heart.

7. What is the function of lymphocytes? Lymphocytes defend the body from invasion by microorganisms. Some attach to the organisms directly while others produce antibodies that circulate in the blood and attack them.